Mems elements on non-planar surface

ABSTRACT

A Micro Electrical Mechanical Systems (MEMS) article including a non-planar surface and a continuous film conforming to the non-planar surface is described. The continuous film includes a polymer layer disposed between two metal layers and is patterned to define one or more MEMS elements.

BACKGROUND

Micro electrical mechanical systems (MEMS) are traditionally made onsilicon wafers or other rigid substrates using batch processes. Thenumber of MEMS elements than can be made at one time is limited by thesize of the silicon wafer. The size limitation and the need for batchprocessing adversely affect the cost effectiveness of traditional MEMSprocessing. In addition, the existence of the rigid substrate limits theapplicability of existing MEMS devices. Accordingly, a need exists forMEMS devices that can be made in a continuous process and that do notrequire a rigid substrate.

SUMMARY

In at least one aspect, the present description provides a flexible filmthat includes a first metallic layer having a first outer major surfaceand a first inner major surface, a first polymer layer adjacent to thefirst metallic layer with the first inner major surface facing the firstpolymer layer, a second metallic layer having a second outer majorsurface and a second inner major surface with the second metallic layerpositioned adjacent to the first polymer layer opposite the firstmetallic layer with the second inner major surface facing the firstpolymer layer. The flexible film includes one or more MEMS elements.Each MEMS element includes a first metallic region in the first metalliclayer, a first voided region in the first polymer layer, and a secondmetallic region in the second metallic layer. The first metallic regionincludes a first perforation and the second metallic region includes aportion that is capable of a movement relative to the first metallicregion.

In some embodiments, the first voided region is aligned with the firstperforation such that a first continuous open region extends between thefirst outer major surface of the first metallic layer to the secondinner major surface of the second metallic layer. In some embodiments,the second metallic region includes a pattern aligned with the firstvoided region such that the first continuous open region extends betweenthe first outer major surface of the first metallic layer to the secondouter major surface of the second metallic layer. In some embodiments,the first perforation includes at least one hole. In some embodiments,the first perforation includes 1 to about 100 holes and each hole has adiameter between about 30 microns and about 200 microns. In someembodiments, each MEMS element further includes one or more viasextending from the second metallic layer to the first metallic layer. Insome embodiments, each MEMS element is selected from the groupconsisting of a spring resonator, a serpentine resonator, afixed-guided-fixed resonator, a cantilever beam, a clamped membrane andan inter-digitated comb-drive resonator. In some embodiments, the firstpolymer layer includes polyimide, polycarbonate, polyethyleneterephthalate, benzocyclobutene polymer, liquid crystal polymer orpolydimethylsiloxane. In some embodiments, one or both of the firstmetallic layer and the second metallic layer includes copper, nickel,chromium, titanium, aluminum, gold, silver, beryllium and alloysthereof.

In some embodiments, the flexible film also includes a second polymerlayer adjacent to the second metallic layer opposite the first polymerlayer and a third metallic layer having a third outer major surface anda third inner major surface where the third metallic layer is positionedadjacent to the second polymer layer opposite the second metallic layerwith the third inner major surface facing the second polymer layer. EachMEMS element may further include a second voided region in the secondpolymer layer and a third metallic region in the third metallic layerwhere the third metallic region includes a second perforation. In someembodiments, the second voided region is aligned with the secondperforation such that a second continuous open region extends betweenthe third outer major surface of the third metallic layer to the secondouter major surface of the second metallic layer.

In some embodiments, the movement of the portion of the second metallicregion that is capable of a movement relative to the first metallicregion is in a direction substantially normal to the second outer majorsurface. In other embodiments, the movement is substantially in a planecontaining the second outer major surface.

In some embodiments, the one or more MEMS elements is a plurality ofMEMS elements. In some embodiments, the film has at least one dimensiongreater than about 100 millimeters. In some embodiments, a roll of theflexible film is provided.

In some embodiments, the first outer major surface is either a firstfree standing surface or is immediately adjacent a first outer polymericlayer or a first adhesive layer and the second outer major surface iseither a second free standing surface or is immediately adjacent asecond outer polymeric layer or a second adhesive layer.

In some embodiments, the first polymer layer has a thickness greaterthan about 0.5 microns and less than about 100 microns. In someembodiments, the thickness of the first polymer layer is greater thanabout 10 microns and less than about 100 microns.

Some embodiments of the present description include an article that hasa surface with the flexible film conformably attached to the surface.

In at least one aspect, the present description provides an articleincluding a three-dimensional object having a non-planar surface and acontinuous film conformably attached to the non-planar surface. Thecontinuous film includes a polymer layer and one or more MEMS elements.Each MEMS element includes a first metallic layer having a first outermajor surface and a first inner major surface where the first metalliclayer is disposed adjacent the polymer layer with the first inner majorsurface facing the polymer layer, a first voided region in the polymerlayer, and a second metallic layer having a second outer major surfaceand a second inner major surface with the second metallic layerpositioned adjacent to the polymer layer opposite the first metalliclayer with the second inner major surface facing the polymer layer. Thefirst metallic layer includes a first perforation. The first voidedregion is aligned with the first perforation such that a continuous openregion extends between the first outer major surface of the firstmetallic layer to the second inner major surface of the second metalliclayer. A portion of the second metallic layer is capable of a movementrelative to the first metallic layer.

In some embodiments, the second metallic layer includes a patternaligned with the first voided region such that the continuous openregion extends between the first outer major surface of the firstmetallic layer to the second outer major surface of the second metalliclayer. In some embodiments, the three-dimensional object is a glove, ashoe, a helmet, a prosthetic device or a robotic structure. In someembodiments, the three-dimensional object is a parallelepiped and theone or more MEMS elements includes a plurality of MEMS accelerometerswhere each MEMS accelerometer is attached to a distinct face of theparallelepiped. In some embodiments, the parallelepiped is a cube andthe plurality of MEMS accelerometers includes three to six MEMSaccelerometers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic top view of a flexible film with a plurality ofMEMS elements;

FIG. 2 is a schematic side view of a portion of a flexible filmincluding a MEMS element;

FIG. 3A is a schematic side view of an un-patterned film;

FIG. 3B is a schematic side view of the un-patterned film of FIG. 3Awith attached masks;

FIG. 3C is a schematic side view of the film of FIG. 3B where areas ofouter metal layers have been etched;

FIG. 3D is a schematic side vie of the film of FIG. 3C where a region ofa polymer layer has been etched;

FIG. 4A is a schematic top view of a region of a metallic layer;

FIG. 4B is a schematic top view of a region of a metallic layer;

FIG. 4C is a schematic top view of a region of a metallic layer;

FIG. 4D is a schematic top view of a region of a metallic layer;

FIG. 4E is a schematic top view of a region of a metallic layer;

FIG. 4F is a schematic top view of a region of a metallic layer;

FIG. 4G is a schematic top view of a region of a metallic layer;

FIG. 5 is a schematic side view of a portion of a flexible filmincluding a MEMS element;

FIG. 6 is a schematic side view of a flexible film including MEMSelements;

FIG. 7 is a schematic perspective view of a portion of an article havinga flexible film including MEMS elements;

FIG. 8 is a schematic perspective view of a flexible film containingMEMS elements;

FIG. 9 is schematic perspective view of an accelerometer; and

FIGS. 10-16 are images of MEMS elements.

DETAILED DESCRIPTION

In the following description, reference is made to the accompanying setof drawings that form a part of the description hereof and in which areshown by way of illustration several specific embodiments. The figuresare not necessarily to scale. In general similar reference numbers areused for similar features in the various embodiments. Unless indicatedotherwise, these similar features may include the same materials, havethe same attributes, and serve the same or similar functions. Additionalor optional features described for one embodiment may also be additionalor optional features for other embodiments, even if not explicitlystated, where appropriate. It is to be understood that other embodimentsare contemplated and may be made without departing from the scope orspirit of the present description. The following detailed description,therefore, is not to be taken in a limiting sense.

Unless otherwise indicated, all numbers expressing feature sizes,amounts, and physical properties used in the specification and claimsare to be understood as being modified in all instances by the term“about.” Accordingly, unless indicated to the contrary, the numericalparameters set forth in the specification and attached claims areapproximations that can vary depending upon the desired propertiessought to be obtained by those skilled in the art utilizing theteachings disclosed herein. The use of numerical ranges by endpointsincludes all numbers within that range (e.g. 1 to 5 includes 1, 1.5, 2,2.75, 3, 3.80, 4, and 5) and any range within that range.

Unless otherwise indicated, the terms “coat,” “coating,” “coated,” andthe like are not limited to a particular type of application method suchas spray coating, dip coating, flood coating, etc., and may refer to amaterial deposited by any method suitable for the material described,including deposition methods such vapor deposition methods, platingmethods, coating methods, etc.

As used herein, layers, components, or elements may be described asbeing adjacent one another. Layers, components, or elements can beadjacent one another by being in direct contact, by being connectedthrough one or more other components, or by being held next to oneanother or attached to one another. Layers, components, or elements thatare in direct contact may be described as being immediately adjacent.

MEMS devices are conventionally made on rigid substrates such assilicon, glass, or ceramic wafers using batch processing techniques. Ithas been difficult to make MEMS elements integrated in an array largerthan a few tens of millimeters because of constraints with the batchprocessing technology that has traditionally been used. An additionallimitation of the traditional approach is the rigidity of the substrate.It is sometimes desirable to attach MEMS devices to a curved surface ofan article or to a flexible article and this is difficult withtraditional MEMS devices due to the rigid substrate. The presentdescription provides for a flexible film containing MEMS devices thatcan be made in a continuous roll-to-roll process. The flexible film canhave a length dimension greater than what can be achieved in traditionalMEMS processing. For example, a flexible film having a length dimensiongreater than 100 millimeters, or greater than about 500 millimeters, orgreater than about 1 meter, or greater than about 10 meters can be madewith MEMS elements integrated into the film substantially over thelength of the film. The resulting film is flexible enough that sectionsof the film can be cut out and conformably attached to articles allowingMEMS-based devices to be made that cannot be made in other ways.

In the present description, MEMS devices are fabricated into a filmhaving a polymer layer with metal layers on each surface of the polymerlayer. The polymer layer acts as both a sacrificial layer in forming theMEMS devices and as a carrier layer that holds the MEMS devicestogether.

FIG. 1 shows flexible film 110 containing a plurality of MEMS elements112. In some embodiments, MEMS elements 112 are arranged in a periodicarray as shown in FIG. 1. In other embodiments, other arrangements arepossible. In some embodiments, the MEMS elements are arranged in aregular, periodic, random, pseudo-random or other pattern. In someembodiments, the MEMS elements are arranged in a periodic pattern in afirst direction but arranged in a random or pseudo-random or otherregular or irregular pattern in a second direction.

FIG. 2 shows a portion of a flexible film 210 that includes anindividual MEMS element 212. Flexible film 210 includes a first metalliclayer 220 having a first outer major surface 222 and a first inner majorsurface 224, a second metallic layer 230 having a second outer majorsurface 232 and a second inner major surface 234, a first polymer layer240 having a first polymer major surface 243 adjacent the first innermajor surface 224 and a second polymer major surface 245 adjacent thesecond inner major surface 234. Flexible film 210 further includes via250, a pattern 260 in second metallic layer 230, a first perforation 270in first metallic layer 220, a first metallic region 282 in firstmetallic layer 220, a second metallic region 284 in second metalliclayer 230, a first voided region 286 in first polymer layer 240, and afirst continuous open region 290. First polymer layer 240 is adjacentthe first metallic layer 220 with the first inner major surface 224facing the first polymer layer 240 and the second metallic layer 230 isdisposed adjacent to the first polymer layer 240 opposite the firstmetallic layer 220 with the second inner major surface 234 facing thefirst polymer layer 240.

The first voided region 286 is aligned with the first perforation 270such that a first continuous open region 290 extends between the firstouter major surface 222 of the first metallic layer 220 to the secondinner major surface 234 of the second metallic layer. In the embodimentshown in FIG. 2, the second metallic region 284 includes a pattern 260aligned with the first voided region 286 such that the first continuousopen region 290 extends between the first outer major surface 222 of thefirst metallic layer 220 to the second outer major surface 232 of thesecond metallic layer 230.

Flexible film incorporating MEMS devices according to the presentdescription can be prepared as illustrated in FIGS. 3A-3D. FIG. 3A showsun-patterned film 301 which includes first metallic layer 320corresponding to first metallic layer 220, second metallic layer 330corresponding to second metallic layer 230, and first polymer layer 340corresponding to first polymer layer 240. First metallic layer 320 hasfirst outer major surface 322 and second metallic layer 330 has secondouter major surface 332. Un-patterned film 301 can be made by depositingor otherwise attaching a first metallic layer 320 and a second metalliclayer 330 to first polymer layer 340. In some embodiments, the metalliclayers are prepared by sputtering a metal coating onto each side offirst polymer layer 340 and then electroplating each metal coating to adesired thickness. Suitable thicknesses for each metallic layer may bein the range of about 3 microns to about 50 microns. Alternatively,polymeric films having metallic layers on each side are commerciallyavailable. For example, UPISEL N from Ube Industries, Japan is apolyimide polymer layer commercially available with copper foil on eachsurface of the polyimide layer.

FIG. 3B shows a first mask 333 attached to first metallic layer 320 anda second mask 335 attached to second metallic layer 330. Second mask 335contains a mask pattern 360 a and first mask 333 contains a maskperforation 370 a.

Suitable masks include photoresists or hard masks such as metal masks.Suitable photoresists include negative acting, aqueous developable,photopolymer compositions such as those disclosed in U.S. Pat. Nos.3,469,982; 3,448,098; 3,867,153; and 3,526,504. Such photoresistsinclude at least a polymer matrix including crosslinkable monomers and aphotoinitiator. Polymers typically used in photoresists includecopolymers of methyl methacrylate, ethyl acrylate and acrylic acid,copolymers of styrene and maleic anhydride isobutyl ester and the like.Crosslinkable monomers may be multiacrylates such as trimethylol propanetriacrylate.

Commercially available aqueous base (e.g., sodium carbonate)developable, negative acting photoresists that may be employed accordingto the present description include polymethylmethacrylates photoresistmaterials such as those available under the trade name RISTON from E.I.duPont de Nemours and Co., e.g., RISTON 4720. Other useful examplesinclude AP850 available from LeaRonal, Inc., Freeport, N.Y., and PHOTECHU350 available from Hitachi Chemical Co. Ltd. Useful alternativesinclude dry film photoresist compositions available under the trade nameAQUA MER from MacDermid, Waterbury, Conn. There are several series ofsuitable AQUA MER photoresists including the “SF” and “CF” series withSF120, SF125, and CF2.0 being representative of these materials.

Aqueous processable photoresists may be laminated over both sides ofun-patterned film 301 using standard laminating techniques. Thethickness of the photoresist may be in the range from about 10 micronsto about 50 microns. Upon exposure of the photoresist on both sides ofthe laminate to actinic radiation (e.g., ultraviolet light or the like)through a mask, the exposed portions of the photoresist become insolubleby crosslinking. The resist is then developed by removal of unexposedpolymer with a dilute aqueous solution, e.g., a 0.5-1.5% sodiumcarbonate solution, until desired mask pattern 360 a and maskperforation 370 a are obtained.

FIG. 3C show pattern 360 in second metallic layer 330 and perforation370 in first metallic layer 320. Pattern 360 and perforation 370 can beformed by etching the metallic layers using any etchant that does notsignificantly compromise the polymer layer when used in a roll-to-rolletching process. Suitable etchants include etchants based on hydrogenperoxide and sulfuric acid such as PERMA ETCH, available fromElectrochemicals, Inc (Maple Plain, Minn.), etchants based on ferricchloride, etchants based on hydrofluoric acid or mixtures ofhydrofluoric acid and nitric acid, etchants based on phosphoric acid,acetic acid and nitric acid, and etchants based on aqua regia(nitro-hydrochloric acid), or any etchant chemistries capable ofreducing the solid metal to an ionic metal species.

An alternative to etching out the desired patterns or perforations inthe metallic layers, is to electroplate metallic layers having thedesired pattern or perforation directly. This can be done by firstsputtering metallic layers on both surfaces of first polymer layer 340then electroplating to produce a desired thickness in each metalliclayer. A suitable thickness is about 1-5 microns. Next a photoresist orhard mask such as a metal mask is applied to each metallic layer and thedesired pattern or perforation is exposed into each photoresist suchthat regions where metal is to be located is not exposed. The resist isthen developed and the unexposed resist removed as described elsewhere.Metal is then electroplated onto both exposed surfaces to a desiredthickness which may be in the range of about 3 microns to about 50microns. The photoresists are then removed leaving the thicker metalregions where desired and thinner metal in the pattern and perforationareas that can be removed by a separate etching step.

FIG. 3D shows first voided region 386 in first polymer layer 340. Firstvoided region 386 can be formed using a polymer etching process. Anysuitable etchant may be used and may vary depending on the polymermaterial. Suitable etchants may include alkali metal salts, e.g.potassium hydroxide; alkali metal salts with one or both ofsolubilizers, e.g., amines, and alcohols, such as ethylene glycol.Suitable chemical etchants for some embodiments of the presentdescription include KOH/ethanol amine/ethylene glycol etchants such asthose described in more detail in U.S. Patent Application PublicationNo. 2007/0120089 (Mao et al.), which is hereby incorporated herein byreference in its entirety. Other suitable etchant chemistries are theKOH/glycine, and KOH/glycine/ethylene diamine chemistries described inmore detail in U.S. Patent Application Publication No. 2013/0207031(Palaniswamy), which is hereby incorporated herein by reference in itsentirety. The KOH/glycine etchant provides a slow, controlled etching.The etching rate can be increased by adding ethylene diamine to theetchant formulation. The polymer may be etched at a temperature in therange of about 50° C. to about 120° C. In some cases a gas phase etchantis used. For example, the polymer may be etched in a reactive ionetching process using O₂ and SF₆ plasma or using O₂ and CF₄ plasma.Other etchant chemistries known in the semiconductor manufacturingindustry may also be used.

After etching the polymer layer, the mask layers 333 and 335 are thenstripped from both sides of the laminate. When photoresists are used asthe mask layers, the photoresists may be removed using a 2-5% solutionof an alkali metal hydroxide in a temperature range of about 25° C. toabout 80° C.

One or more vias, such as via 250 shown in FIG. 2, can be included inthe flexible film by including a pattern for the vias in second mask335, etching second metallic layer 330 in the region of the vias,etching first polymer layer 340 in the region of the vias, and thenmetalizing the etched region using standard metallization techniques toproduce the vias.

All of the process steps illustrated in FIGS. 3A-3D can be carried outin a continuous roll-to-roll process using standard continuous webprocessing techniques. The continuous process may be carried out inautomated fashion using equipment designed to transport a web materialthrough the process sequence from a supply roll to a wind-up roll, whichcollects mass produced flexible film that includes MEMS elements. Theprocessing equipment may include a web handling device that has avariety of processing stations for applying, exposing and developingphotoresist coatings, as well as etching and/or plating the metalliclayers and etching the polymer film. Etching stations may include anumber of spray bars with jet nozzles that spray etchant on the movingweb to etch those parts of the web not protected by crosslinkedphotoresist. Additional suitable roll-to-roll processes are described inU.S. Pat. No. 5,055,416 (Weber) and U.S. Pat. No. 8,486,593 (Haase etal.), for example. The process described in the present descriptiontakes advantage of the simultaneous use of the polymeric web as the coresubstrate material onto which MEMS elements are fabricated and as thesacrificial material that when removed from localized regions, releasesthe free moving structures from the fixed structures of a MEMS device orMEMS sensor.

FIG. 4A shows a first metallic region 482 of first metallic layer 420.First metallic region 482 includes perforation 470. First metallic layer420, which corresponds to first metallic layer 220, is one layer of aflexible film of the present description. In some embodiments,perforation 470 includes at least one hole as shown in FIG. 4A. In someembodiments, perforation 470 includes 1 to about 100 holes. The numberand size of the holes may be chosen so that the polymer layer can beeffectively etched. Each hole diameter may be greater than about 0.4microns, or greater than about 1 micron, or greater than about 10microns or greater than about 30 microns and each hole diameter may besmaller than about 100 microns or smaller than about 150 microns, orsmaller than about 200 microns. For example, in some embodiments, eachhole has a diameter between about 30 microns and about 200 microns.Typically, a larger number of smaller holes are chosen when gas phaseetching is used and a smaller number of larger holes are used withliquid phase etching. The upper size of the hole is limited by the sizeof the MEMS device. Each MEMS device may have a size (e.g., length orwidth in the plane of the MEMS device) greater than about 1 micron orgreater than about 10 microns and less than about 5 mm or less thanabout 1 mm.

FIG. 4B shows a second metallic region 484 of second metallic layer 430having second outer major surface 432. Second metallic region 484includes pattern 460 and a movable portion 481. Second metallic layer430, which corresponds to second metallic layer 230, is one layer of aflexible film of the present description. The flexible film alsoincludes a first metallic layer 420 shown in FIG. 4A corresponding tofirst metallic layer 220. Movable portion 481 is capable of momentrelative to the first metallic layer 420. In the embodiment shown inFIG. 4B, the movement of movable portion 481 is substantially normal tosecond outer major surface 432 (i.e., into or out of the plane of FIG.4B). In other embodiments, other types of movement are possible.

Any type of MEMS device that can be made into parallel metal layers maybe included in the flexible film of the present description. The MEMSdevice resulting from second metallic region 484 of FIG. 4B is anexample of a spring resonator. FIG. 4C shows an alternate secondmetallic region 484 c of second metallic layer 430 c having second outermajor surface 432 c. The MEMS device resulting from second metallicregion 484 c is an example of a crab-leg resonator which is a type ofspring resonator. Movable portion 481 c is capable of movement in adirection substantially normal to second outer major surface 432 c. FIG.4D shows an alternate second metallic region 484 d of second metalliclayer 430 d having second outer major surface 432 d. The MEMS deviceresulting from second metallic region 484 d is an example of aninter-digitated comb-drive resonator. Movable portion 481 d is capableof movement substantially in a plane containing second outer majorsurface 432 d (i.e., in the plane of FIG. 4D).

Other possible types of MEMS devices include fixed-guided-fixedresonators, cantilever beams and serpentine resonators. Referring toFIG. 4E, a fixed-guided-fixed resonator can be made using secondmetallic region 484 e of second metallic layer 430 e having movableportion 481 e. Referring to FIG. 4F, a cantilever beam device can bemade using second metallic region 484 f of second metallic layer 430 fhaving movable portion 481 f. Referring to FIG. 4G, a serpentineresonator can be made using second metallic region 484 g of secondmetallic layer 430 g having movable portion 481 g. Another possible MEMSdevice is a clamped membrane or clamped diaphragm device which is madeby simply not etching a pattern into the second metallic layer. In thiscase the voided region in the first polymer layer allows movement of ametallic region of the second metallic layer adjacent the voided regionby deflection of the metallic region. This type of MEMS device can beuseful as a pressure sensor, for example. In some embodiments, theflexible film contains an array of one type of MEMS device. In otherembodiments, the flexible film includes multiple types of MEMS devices.

The MEMS devices may be sensors or actuators and may be used as pressuresensors, touch sensors, impact sensors, accelerometers, microphones, andthe like. For example, in some embodiments the MEMS devices may beaccelerometers and may be used for impact sensing or for vibrationsensing. In other embodiments, the MEMS devices may be pressure sensorsand may be used to determine pressure distribution. In otherembodiments, the MEMS devices may be microphones and a film containingMEMS microphones can provide a conformable microphone array.

Images of MEMS elements made using the continuous web processingtechniques described previously are shown in FIGS. 10-15. The dimensionsof the MEMS elements are in a range of about 0.5 mm to about 2.5 mm.FIG. 10 shows a crab-leg resonator having second metallic layer 1030,which includes movable portion 1081, facing out of the plane of thefigure. First metallic layer 1020, which includes perforation 1070, isvisible through etched portions of second metallic layer 1030. FIG. 11shows a serpentine spring resonator with second metallic layer 1130,which includes movable portion 1181, facing out of the plane of thefigure. First metallic layer 1120, which includes perforation 1170, isvisible through etched portions of second metallic layer 1130. FIG. 12shows a fixed-guided-fixed resonator with second metallic layer 1230,which includes movable portion 1281, facing out of the plane of thefigure. First metallic layer 1220, which includes perforation 1270, isvisible through etched portions of second metallic layer 1230. FIG. 13shows a cantilever beam resonator with second metallic layer 1330, whichincludes movable portion 1381, facing out of the plane of the figure.First metallic layer 1320, which includes perforation 1370, is visiblethrough etched portions of second metallic layer 1330. FIG. 14 shows aresonator with second metallic layer 1430, which includes movableportion 1481, facing out of the plane of the figure. First metalliclayer 1420, which includes perforation 1470, is visible through etchedportions of second metallic layer 1430. FIG. 15 shows a clamped membraneresonator with first metallic layer 1520, which includes perforation1570, facing out of the plane of the figure. Second metallic layer 1530,which includes movable portion 1581, is visible through perforation1570. The holes visible in FIGS. 10-15 have a diameter of about 150microns. The spring elements that connect the movable portion of thesecond metallic layer to the remaining portion of portion of the secondmetallic layer in these examples have a width of about 75 microns. Thedimensions of the movable portions (resonators) in FIGS. 10-12 are about600 microns by 600 microns.

In the embodiments shown in FIGS. 10-14, a relatively large amount ofmetal has been removed from the second metal layer near the movableportions (resonators). In other embodiments, less metal is removed fromthe vicinity of the resonator (movable portion). By limiting the amountof metal removed to relatively localized regions near the resonator, theyield can be improved since such localized regions can be moreefficiently etched. An example of this is illustrated in FIG. 16 whichshows a crab-leg spring resonator with second metallic layer 1630 facingout of the plane of the figure. Second metallic layer 1630 includesmovable portion 1681. First polymer layer 1640 is visible where secondmetallic layer 1630 has been removed. The dimensions of movable portion1681 in FIG. 16 are about 500 microns by 600 microns.

In some cases it may be desired to have a symmetrical MEMS device wherethe movable portion of a metallic layer is near the center of a filmstack. FIG. 5 shows a portion of a flexible film 510 that includes anindividual MEMS element 510 a. Flexible film 510 includes a firstmetallic layer 520 having a first outer major surface 522 and a firstinner major surface 524, a second metallic layer 530 having a secondouter major surface 532 and a second inner major surface 534, a firstpolymer layer 540 having a first polymer major surface 543 adjacent thefirst inner major surface 524 and a second polymer major surface 545adjacent the second inner major surface 534. Flexible film 510 alsoincludes a second polymer layer 580 having a third polymer major surface583 and a fourth polymer major surface 585 and a third metallic layer591 having third outer major surface 592 and third inner major surface594. Flexible film 510 further includes via 550, a pattern 560 in secondmetallic layer 530, a first perforation 570 in first metallic layer 520,a first metallic region 582 in first metallic layer 520, a secondmetallic region 584 in second metallic layer 530, a third metallicregion 582 a in third metallic layer 591, a first voided region 586 infirst polymer layer 540, a second voided region 586 a in second polymerlayer 580, a first continuous open region 590, a second continuous openregion 590 a, and a second perforation 597.

First polymer layer 540 is adjacent the first metallic layer 520 withthe first inner major surface 524 facing the first polymer layer 540 andthe second metallic layer 530 is disposed adjacent to the first polymerlayer 540 opposite the first metallic layer 520 with the second innermajor surface 534 facing the first polymer layer 540. Second polymerlayer 580 is disposed adjacent the second metallic layer 530 oppositethe first polymer layer 540. The third metallic layer 591 is disposedadjacent the second polymer layer 580 opposite the second metallic layer530 with the third inner major surface 594 facing the second polymerlayer 580.

The first voided region 586 is aligned with the first perforation 570such that a first continuous open region 590 extends between the firstouter major surface 522 of the first metallic layer 520 to the secondinner major surface 534 of the second metallic layer 530. Similarly, thesecond voided region 586 a is aligned with the second perforation 597such that a second continuous open region 590 a extends between thethird outer major surface 592 of the third metallic layer 591 to thesecond outer major surface 532 of the second metallic layer 530. In theembodiment shown in FIG. 5, pattern 560 is such that first continuousopen region 590 and second continuous open region 590 a form acontinuous open region extending between first outer major surface 522and third outer major surface 592. Flexible film 510 may be made byfirst making a flexible film as described elsewhere having a firstpolymer layer 540 with a first metallic layer 520 and a second metalliclayer 530 having a pattern 560. Then a second polymer layer 580 may belaminated using standard lamination techniques to the second metalliclayer 530. A third metallic layer 591 may then be deposited on thesecond polymer layer 580 opposite the second metallic layer 530 oralternatively the second polymer layer 580 may have the third metalliclayer 591 attached prior to lamination of the second polymer layer 580to the patterned second metallic layer 530. Second perforation 597 maybe made in third metallic layer 591 using the techniques describedelsewhere for producing first perforation 570. Second voided region 586a can then be made in second polymer layer 580 using the techniquesdescribed elsewhere for producing first voided region 586.

Suitable polymeric materials for use in polymer layers of the flexiblefilms of the present description include polyesters, polycarbonates,liquid crystal polymers, polyimides, benzocyclobutene polymer,polydimethylsiloxane and polyethylene terephthalate (PET). Suitablepolyimides include those available under the trade names KAPTON,available from DuPont (Wilmington, Del.); APICAL, available from KanekaCorporation (Otsu, Japan); SKC Kolon PI, available from SKC Kolon PI Inc(Korea); and UPILEX and UPISEL including UPILEX S, UPILEX SN, and UPISELVT, all available from Ube Industries (Japan). These UPILEX and UPISELpolyimides are made from monomers such as biphenyl tetracarboxylicdianhydride (BPDA) and phenyl diamine (PDA).

Polymer layers thinner than about 1 micron may be difficult to handle ina roll-to-roll process. In many embodiments of the present descriptionthe polymer layers have a thickness greater than about 1 micron. Polymerlayers thicker than about 200 microns may result in a stiffness in theflexible films that may be too high for some applications. In addition,etching such thick polymer films may be difficult or time consuming. Insome embodiments, the thickness of the polymer layer is greater thanabout 0.5 microns, or greater than about 1 micron, or greater than about2 microns, or greater than about 5 microns, or greater than about 10microns and less than about 200 microns, or less than about 100 micronsor less than about 50 microns.

In some embodiments, polyimide film is used as a polymer layer. Manycommercially available polyimide films include monomers of pyromelliticdianhydride (PMDA), or oxydianiline (ODA), or biphenyl dianhydride(BPDA), or phenylene diamine (PDA). Polyimide film products believed tobe made using one or more of these monomers are designated under thetrade name KAPTON H, K, E films (DuPont, Wilmington, Del.) and APICALAV, NP films (Kaneka Corporation, Japan).

Another suitable polyimide film is APICAL HPNF polyimide film (KanekaCorporation, Japan), which is believed to be a copolymer that derivesits ester unit containing structure from polymerizing of monomersincluding p-phenylene bis(trimellitic acid monoester anhydride). To oneof ordinary skill in the art, it would be reasonable to synthesize otherester unit containing polyimide polymers depending upon selection ofmonomers similar to those used for APICAL HPNF. Such syntheses couldexpand the range of polyimide polymers for films, which, like APICALHPNF, may be controllably etched. Materials that may be selected toincrease the number of ester containing polyimide polymers include1,3-diphenol bis(anhydro-trimellitate), 1,4-diphenolbis(anhydro-trimellitate), ethylene glycol bis(anhydro-trimellitate),biphenol bis(anhydro-trimellitate), oxy-diphenolbis(anhydro-trimellitate), bis(4-hydroxyphenyl sulfide)bis(anhydro-trimellitate), bis(4-hydroxybenzophenone)bis(anhydro-trimellitate), bis(4-hydroxyphenyl sulfone)bis(anhydro-trimellitate), bis(hydroxyphenoxybenzene),bis(anhydro-trimellitate), 1,3-diphenol bis(aminobenzoate), 1,4-diphenolbis(aminobenzoate), ethylene glycol bis(aminobenzoate), biphenolbis(aminobenzoate), oxy-diphenol bis(aminobenzoate), bis(4aminobenzoate) bis(aminobenzoate), and the like.

Liquid crystal polymers (LCP) may also be used as a polymer layer.Suitable films of liquid crystal polymers include aromatic polyestersincluding copolymers containing p-phenyleneterephthalamide such as BIACfilm (Japan Gore-Tex Inc., Okayama-Ken, Japan) and copolymers containingp-hydroxybenzoic acid such as LCP CT film (Kuraray Co., Ltd., Okayama,Japan). Suitable films also include ESPANEX films (Nippon Steel &Sumikin Chemical Co. Ltd).

Other suitable films include extruded and tentered (biaxially stretched)liquid crystal polymer films. For example, a process described in U.S.Pat. No. 4,975,312 provided multiaxially (e.g., biaxially) orientedthermotropic polymer films of commercially available liquid crystalpolymers (LCP) identified by the trade names VECTRA (naphthalene based,available from Hoechst Celanese Corp.) and XYDAR (biphenol based,available from Amoco Performance Products).

Polycarbonate film may also be used as a polymer layer. Examples ofsuitable polycarbonate materials include substituted and unsubstitutedpolycarbonates; polycarbonate blends such as polycarbonate/aliphaticpolyester blends, including the blends available under the trade nameXYLEX from GE Plastics, Pittsfield, Mass.,polycarbonate/polyethyleneterephthalate (PC/PET) blends,polycarbonate/polybutyleneterephthalate (PC/PBT) blends, andpolycarbonate/poly(ethylene 2,6-naphthalate) ((PPC/PBT, PC/PEN) blends,and any other blend of polycarbonate with a thermoplastic resin; andpolycarbonate copolymers such as polycarbonate/polyethyleneterephthalate(PC/PET) and polycarbonate/polyetherimide (PC/PEI).

Another type of polymeric material suitable for use in the presentdescription is a laminate such as a polycarbonate laminate or a PETlaminate. Such a laminate may have at least two different polymericlayers adjacent to each other or may have at least one polycarbonatelayer adjacent to a thermoplastic material layer (e.g., LEXAN GS 125DLwhich is a polycarbonate/polyvinylidene fluoride (PVDF) laminate from GEPlastics). Polymeric materials may also be filled with carbon black,silica, alumina and the like or they may contain additives such as flameretardants, UV stabilizers, pigments and the like. Polymeric materialsmay include microparticles or nanoparticles for application specificconstructions or for modifying the material properties for enhancedperformance, increased reliability or durability.

Any polymeric material for which any etchant provides a desirable etchrate and desirable result may be used for any polymer layer of thepresent description. Examples of other suitable polymers includepolyamide-imides and polyesters such as amorphous PET, polyethylenenaphthalate (PEN), polybutylene terephthalate (PBT) and the like.

Suitable metals for use in any metal layer of the present descriptioninclude any metal that can be chemically etched. Examples includecopper, nickel, chromium, titanium, silver, aluminum, gold, berylliumand alloys thereof, such as beryllium-copper alloy.

Since the flexible films of the present description can be made incontinuous roll-to-roll processes, larger length scales can be achievedcompared to conventional silicon wafer fabrication techniques. In someembodiments, the flexible film has a length greater than about 100millimeters, 500 millimeters, or greater than about 1 m, or greater thanabout 3 m, or greater than about 10 m, or even greater than about 30 m.In some embodiments the flexible film has a length scale in the range ofabout 1 m to about 500 m. In some embodiments, the flexible filmcontains at least 10⁴ MEMS devices or at least 10⁶ MEMS devices or atleast 10⁹ MEMS devices. In some embodiments, the flexible film containsat least 10⁴ MEMS devices or at least 10⁶ MEMS elements or at least 10⁹MEMS elements and contains less than 10¹⁵ MEMS elements or less thanless than 10²⁰ MEMS elements. In some embodiments, one or more MEMSelements are fabricated at one or more locations specific to an endapplication. In some embodiments, a roll of the flexible film isprovided. In some embodiments, a flexible film may be singulated so thatflexible films having only one MEMS element or having 1 to about 10 or 1to about 100 MEMS elements are produced.

In some embodiments, the first outer major surface is a free standingsurface. In other embodiments, a first coating may be applied to thefirst outer major surface. The first coating may be a first outerpolymeric layer or a first adhesive layer. A first outer polymeric layermay be used as a protective layer. Similarly, in some embodiments,second outer major is a free standing surface, while in otherembodiments a second coating may be applied to second outer majorsurface. The second coating may be a second outer polymeric layer or asecond adhesive layer. A second outer polymeric layer may be used as aprotective layer. An adhesive layer can be applied to either the firstouter major surface or the second outer major surface in order toconformably attach the film to a surface of an article. For example, anarray of MEMS accelerometers or MEMS microphones may be conformablyattached to a surface of an article.

FIG. 6 shows flexible film 600 that includes flexible film 610 andadhesive layer 611. Flexible film 610 includes MEMS elements 612 and hasa first outer major surface 622 and a second outer major surface 632which is a free standing surface. Adhesive layer 611 is attached tofirst outer major surface 622. Since neither first outer major surface622 nor second outer major surface 632 is attached to silicon or otherrigid substrates, flexible film 600 could not be obtained inconventional silicon wafer manufacturing processes where MEMS devicesare made on a silicon substrate.

Having MEMS devices incorporated into a flexible film, allowsintegration with various articles more readily than conventional MEMSdevices. FIG. 7 shows a portion 700 of an article having a surface 702.Flexible film 710, includes MEMS elements 712, is conformably attachedto surface 702. Surface 702 may be substantially flat or it may be anon-planar surface.

In one aspect of the present description, an article includes athree-dimensional object having a non-planar surface. The non-planarsurface may be a curved surface or it may consist of two or more planarsurfaces joined together—for example, the surface of a cube. Thenon-planar surface may be non-planar when the article is in a firststate but planar or approximately planar when the article is in a secondstate. This may be the case for a flexible article, for example, thathas a surface which is non-planar when the article is subject to astress, but is substantially planar when the article is un-stressed. Forexample, the non-planar surface may be a surface in a shoe sole which iscurved when the shoe is flexed. The surface may be an exterior surfaceor the surface may be an embedded surface—for example, an interfacebetween two layers. The article includes a flexible film conformablyattached to the surface where the flexible film contains at least oneMEMS element. Such a flexible film can be made by cutting out a portionof any of the flexible films of the present description describedelsewhere, where the cut-out portion contains at least one MEMS element.This allows one or more MEMS elements to be integrated into an articleas an integral part of a continuous film. Suitable articles include aglove, a helmet, a shoe, a prosthetic device or a robotic structure suchas a robotic arm.

In some embodiments, a flexible film contains a plurality of MEMS-basedpressure sensors. Such a film can be used in an article such as a shoesole, for example, in order to collect data regarding the pressuredistribution on the shoe as a wearer walks or runs. Such data could beuseful in podiatry or in sports science. In some embodiments, thepressure sensors are electrically connected in common rows and columnsfor multiplex data transfer. In some embodiments, electrical traceswhich connect the pressure sensors together are formed by etching asuitable pattern in a metal layer of the flexible film—for example, insecond metallic layer 230 of FIG. 2. In some embodiments, an article,such as a shoe, incorporating the flexible film includes a data storageunit for receiving and storing data from the pressure sensors. In someembodiments, the article may include a transmitter for receiving andtransmitting data from the pressure sensors. In some embodiments, thearticle includes a circuit for conditioning the data from the pressuresensors. In some embodiments, the article includes a battery or otherpower source for supplying power to the sensors and associatedelectronics. In some embodiments, a battery is integrated into thecircuit using a printing or plating technique.

In some embodiments, a three-directional accelerometer is obtained byconformably attaching a flexible film having three or more MEMSaccelerometers to a three-dimensional object. In some embodiments, thethree-dimensional object is a parallelepiped and each MEMS accelerometeris attached to a distinct face of the parallelepiped. The parallelepipedmay be a cube and the flexible film may include three to six MEMSaccelerometers with each MEMS accelerometer attached to a distinct faceof the cube. In some embodiments, a multi-axis (e.g., three or moreaxes) accelerometer system is obtained by conformably attaching aflexible film having a plurality of MEMS elements onto a flat or curvedsurface. Such an accelerometer system can be used for sensingacceleration about any arbitrary axis thereby allowing an angular impactresponse surface to be created.

FIG. 8 shows flexible film 810 containing MEMS elements 812 and traces808. Flexible film 810 can be prepared by cutting out a section from alarger flexible film containing MEMS elements. Traces 808 can be made bysuitably etching a pattern in the first or second metallic layer offlexible film 810. Alternatively, traces 808 can be applied by using aprinting process to deposit conductive material. FIG. 9 shows cube 900with a flexible film 910 conformably attached to the cube 900. Flexiblefilm 910, which corresponds to flexible film 810, includes MEMS elements912. MEMS elements 912 may be MEMS accelerometers.

In some embodiments, a flexible film including MEMS accelerometers isattached to or integrated into an article for use as an impact sensor.For example, a flexible film including MEMS accelerometers can beattached to or integrated into a helmet for use as an impact sensor. Insome embodiments, the article includes a circuit for signalconditioning, a power source such as a battery and a memory unit or adata transmittal unit. In some embodiments, the article includes LEDforce indicator lights that illuminate when a threshold force has beendetected.

In some embodiments, a circuit or circuits are included in the flexiblefilm. In some embodiments, the circuits include a radio frequency (RF)radio microchip, capable of receiving and sending MEMS sensor data. Insome embodiments, the circuits include application specific firmwarecapable of managing and sending data to an Android® or iOS® applicationrunning on a mobile computing device, smart phone, or smart appliance.

The following is a list of exemplary embodiments of the presentdescription:

Embodiment 1 is a flexible film, comprising:

-   -   a first metallic layer having a first outer major surface and a        first inner major surface;    -   a first polymer layer adjacent the first metallic layer, the        first inner major surface facing the first polymer layer;    -   a second metallic layer having a second outer major surface and        a second inner major surface, the second metallic layer disposed        adjacent the first polymer layer opposite the first metallic        layer, the second inner major surface facing the first polymer        layer,

wherein the flexible film includes one or more MEMS elements, each MEMSelement including^(.)

-   -   a first metallic region in the first metallic layer, the first        metallic region including a first perforation;    -   a first voided region in the first polymer layer; and    -   a second metallic region in the second metallic layer, the        second metallic region including a portion that is capable of a        movement relative to the first metallic region.

Embodiment 2 is the flexible film of Embodiment 1, wherein the firstvoided region is aligned with the first perforation such that a firstcontinuous open region extends between the first outer major surface ofthe first metallic layer to the second inner major surface of the secondmetallic layer.

Embodiment 3 is the flexible film of Embodiment 2, wherein the secondmetallic region includes a pattern aligned with the first voided regionsuch that the first continuous open region extends between the firstouter major surface of the first metallic layer to the second outermajor surface of the second metallic layer.

Embodiment 4 is the flexible film of Embodiment 1, wherein the firstperforation includes at least one hole.

Embodiment 5 is the flexible film of Embodiment 4, wherein the firstperforation includes 1 to about 100 holes and each hole has a diameterbetween about 30 microns and about 200 microns.

Embodiment 6 is the flexible film of Embodiment 1, wherein each MEMSelement further includes one or more vias extending from the secondmetallic layer to the first metallic layer.

Embodiment 7 is the flexible film of Embodiment 1, wherein each MEMSelement is selected from the group consisting of a spring resonator, aserpentine resonator, a fixed-guided-fixed resonator, a cantilever beam,a clamped membrane and an inter-digitated comb-drive resonator.

Embodiment 8 is the flexible film of Embodiment 1, wherein the firstpolymer layer includes a polymer selected from the group consisting ofpolyimide, polycarbonate, polyethylene terephthalate, benzocyclobutenepolymer, liquid crystal polymer and polydimethylsiloxane.

Embodiment 9 is the flexible film of Embodiment 1, wherein at least oneof the first metallic layer and the second metallic layer includes ametal selected from the group consisting of copper, nickel, chromium,titanium, aluminum, gold, silver, beryllium and alloys thereof.

Embodiment 10 is the flexible film of Embodiment 1, further comprising:

-   -   a second polymer layer adjacent the second metallic layer        opposite the first polymer layer;    -   a third metallic layer having a third outer major surface and a        third inner major surface, the third metallic layer disposed        adjacent the second polymer layer opposite the second metallic        layer, the third inner major surface facing the second polymer        layer;

wherein each MEMS element further includes:

-   -   a second voided region in the second polymer layer,    -   and a third metallic region in the third metallic layer, the        third metallic region including a second perforation.

Embodiment 11 is the flexible film of Embodiment 10, wherein the secondvoided region is aligned with the second perforation such that a secondcontinuous open region extends between the third outer major surface ofthe third metallic layer to the second outer major surface of the secondmetallic layer.

Embodiment 12 is the flexible film of Embodiment 1, wherein the movementis in a direction substantially normal to the second outer majorsurface.

Embodiment 13 is the flexible film of Embodiment 1, wherein the movementis substantially in a plane containing the second outer major surface.

Embodiment 14 is the flexible film of Embodiment 1, wherein the one ormore MEMS elements is a plurality of MEMS elements.

Embodiment 15 is the flexible film of Embodiment 1, wherein the flexiblefilm has at least one dimension greater than about 100 millimeters.

Embodiment 16 is a roll of the flexible film of Embodiment 1.

Embodiment 17 is the flexible film of Embodiment 1, wherein the firstouter major surface is either a first free standing surface or isimmediately adjacent a first outer polymeric layer or a first adhesivelayer and the second outer major surface is either a second freestanding surface or is immediately adjacent a second outer polymericlayer or a second adhesive layer.

Embodiment 18 is the flexible film of Embodiment 1, wherein the firstpolymer layer has a thickness greater than about 0.5 microns and lessthan about 100 microns.

Embodiment 19 is the flexible film of Embodiment 18, wherein thethickness is greater than about 10 microns.

Embodiment 20 is an article comprising a surface and the flexible filmof Embodiment 1, wherein the flexible film is conformably attached tothe surface.

Embodiment 21 is an article comprising:

-   -   a three-dimensional object having a non-planar surface; and    -   a continuous film conformably attached to the non-planar        surface, the continuous film including a polymer layer and one        or more MEMS elements, each of the one or more MEMS elements        including:        -   a first metallic layer having a first outer major surface            and a first inner major surface, the first metallic layer            disposed adjacent the polymer layer, the first inner major            surface facing the polymer layer, the first metallic layer            including a first perforation;        -   a first voided region in the polymer layer;        -   a second metallic layer having a second outer major surface            and a second inner major surface, the second metallic layer            disposed adjacent the polymer layer opposite the first            metallic layer, the second inner major surface facing the            polymer layer,        -   wherein the first voided region is aligned with the first            perforation such that a continuous open region extends            between the first outer major surface of the first metallic            layer to the second inner major surface of the second            metallic layer and wherein a portion of the second metallic            layer is capable of a movement relative to the first            metallic layer.

Embodiment 22 is the article of Embodiment 21, wherein the secondmetallic layer includes a pattern aligned with the first voided regionsuch that the continuous open region extends between the first outermajor surface of the first metallic layer to the second outer majorsurface of the second metallic layer.

Embodiment 23 is the article of Embodiment 21, wherein thethree-dimensional object is selected from the group consisting of aglove, a shoe, a helmet, a prosthetic device and a robotic structure.

Embodiment 24 is the article of Embodiment 21, wherein thethree-dimensional object is a parallelepiped and the one or more MEMSelements includes a plurality of MEMS accelerometers, each MEMSaccelerometer attached to a distinct face of the parallelepiped.

Embodiment 25 is the article of Embodiment 24, wherein theparallelepiped is a cube and the plurality of MEMS accelerometersincludes three to six MEMS accelerometers.

Descriptions for elements in figures should be understood to applyequally to corresponding elements in other figures, unless indicatedotherwise. The present invention should not be considered limited to theparticular embodiments described above, as such embodiments aredescribed in detail in order to facilitate explanation of variousaspects of the invention. Rather, the present invention should beunderstood to cover all aspects of the invention, including variousmodifications, equivalent processes, and alternative devices fallingwithin the scope of the invention as defined by the appended claims andtheir equivalents.

What is claimed is:
 1. A Micro Electrical Mechanical Systems (MEMS)article, comprising: a non-planar surface; and a continuous filmconforming to the non-planar surface, the continuous film comprisingfirst and second metallic layers and a first polymer layer disposedtherebetween, the continuous film being patterned to define one or moreMEMS elements therein.
 2. The article of claim 1, wherein the continuousfilm is patterned such that each MEMS element in the one or more MEMSelements includes: a first metallic region in the first metallic layer,the first metallic region including a first perforation; a first voidedregion in the first polymer layer, the first voided region extendingcontinuously through a thickness of the first polymer layer; and asecond metallic region in the second metallic layer, the second metallicregion including a portion that is capable of a movement relative to thefirst metallic region.
 3. The article of claim 2, wherein the firstvoided region is aligned with the first perforation.
 4. The article ofclaim 3, wherein the second metallic region includes a pattern alignedwith the first voided region.
 5. The article of claim 2, wherein thefirst perforation includes 1 to about 100 holes and each hole has adiameter between about 30 microns and about 200 microns.
 6. The articleof claim 2, wherein the continuous film further comprises: a secondpolymer layer disposed on the second metallic layer opposite the firstpolymer layer; and a third metallic layer disposed on the second polymerlayer opposite the second metallic layer.
 7. The article of claim 6,wherein the continuous film is patterned such that each MEMS element inthe one or more MEMS elements further includes: a second voided regionin the second polymer layer; and a third metallic region in the thirdmetallic layer, the third metallic region including a secondperforation.
 8. The article of claim 7, wherein the second voided regionis aligned with the second perforation.
 8. The article of claim 1,wherein the one or more MEMS elements is a plurality of MEMS elements.9. The article of claim 1, wherein a parallelepiped comprises thenon-planar surface, and the one or more MEMS elements includes aplurality of MEMS accelerometers comprising a first MEMS accelerometerattached to a first face of the parallelepiped and a second MEMSaccelerometer attached to a different second face of the parallelepiped.10. The article of claim 9, wherein the plurality of MEMS accelerometersincludes three to six MEMS accelerometers, each attached to a differentface of the parallelepiped.
 11. The article of claim 10, wherein theparallelepiped is a cube.
 12. The article of claim 1, wherein thecontinuous film is conformably attached to the non-planar surfacethrough an adhesive layer.
 13. The article of claim 1, wherein each MEMSelement further includes one or more vias extending through the secondmetallic layer.
 14. The article of claim 1, wherein each MEMS element isselected from the group consisting of a spring resonator, a serpentineresonator, a fixed-guided-fixed resonator, a cantilever beam, a clampedmembrane and an inter-digitated comb-drive resonator.
 15. The article ofclaim 1, wherein the first polymer layer includes a polymer selectedfrom the group consisting of polyimide, polycarbonate, polyethyleneterephthalate, benzocyclobutene polymer, liquid crystal polymer andpolydimethylsiloxane.
 16. The article of claim 1, wherein at least oneof the first metallic layer or the second metallic layer includes ametal selected from the group consisting of copper, nickel, chromium,titanium, aluminum, gold, silver, beryllium and alloys thereof.